SCURRIA. 63 



clouded with brown. Edge of the shell deeply siniiated by the ribs, 

 articulated with black ; inside of this there is a narrow blue band. 



Length 54, breadth 44, alt. 20 mill. 



Chili. 



P. zebrina Lesson, Voy. de la Coquille, p. 417, 1830. — Orb., Voy. 

 Amer. Merid., p. 480, t. 65, f. 1-3. — P. concepcionensis Less., L c, 

 p. A\%.—Lottia zebrina Gld., Moll. U. S. Expl. Exped., p. 352, t. 

 130, f. 460. — Tectura zebrina Gray. — Lottia variabilis Gray^ 

 Beechey's Voy., t. 39, f. 3, 4, but not f. 5. — Scurria {?) zebrina 

 Dall, Amer. Jouri^. Conch, vi, p. 264. 



The color pattern of triangular black spots is characteristic when 

 not obscured by erosion. The eroded shell is gray, or purple tinged, 

 with a darker apical tract. 



S. parasitica Orbigny. PI. 4, figs. 74, 75, 76. 



Shell oval, rounded-conical, solid and strong, the apex at the 

 anterior third, rounded ofl:' by erosion ; front slope nearly straight, 

 posterior slope convex. Surface closely and finely radiately striated 

 all over ; light gray or whitish, with broad and narrow radiating 

 blackish-gray stripes, about 11 in number. Edge of shell smooth 

 even. 



Inside white, more or less clouded with chestnut inside the muscle- 

 scar ; the yellowish-white border is rather broad, and alternately 

 light and dark the one or the other frequently predominating. 



Length 22J, breadth 17, alt. 7^ mill. 



Valparaiso, etc., Chili. 



P. parasitica Orb., Voy. Amer. Merid. p. 481, t. 81, f. 1-3. — 

 Lottia cymbiola Gld., Moll. U. S. Expl. Exped. p. 350, t. 29, f. 

 453. — Not Patella parasitica Rve. — P. (Acmcea) leucophcea Phil., 

 Zeitschr. f. Mai. 1846, p. 22 ; Abbild. iii, t. 2, f. 10.—? A. puncta- 

 tissima Phil., Zeitschr. f. Mai 1846, p. 23; Abbild. iii, t. 2, f 11. 



A finely striated, arched or dome-shaped species. The basal side- 

 margins are usfially arcuate. It lives upon other shells, usually S. 

 zebrina. There is but little variation in this species, and the several 

 names are completely synonymous. 



The following form seems to be closely allied, the distinction being 

 founded mainly on the finely speckled or dotted surface — a common 

 aspect of variation in West American limpets. 



